Thousands of people play the game of "BINGO", at home or at fairs or at bingo halls. The game utilizes cards which typically carry 25 numbers thereon in 5 rows and columns. As numbers are called out the players cover the called numbers on their cards until a predetermined set of numbers has been covered, at which point the player is a "winner". The predetermined set may be a line of 5 numbers running vertically, horizontally or corner-to-corner on the card or it might be the entire card.
It is necessary to keep track of the numbers that have been called during any particular game. Typically this has been done by covering the called number on one's card with a small disc. The disadvantage of this is that it is easy to displace the discs if the card is accidentally moved, thereby making it difficult for the player to resume play, unless he can remember the exact location of his discs.
An alternative to the use of discs is the so-called "dabber", a cylindrical bottle filled with an indellible but transparent ink and having a check-valve operated applicator head, usually of a foam material. When a number is called the player inverts the bottle and presses the head on the number called. A colored spot is left by the head on the called number. While these dabbers are an advance over discs they too have certain drawbacks. For example, the check-valves occasionally leak and ink can run onto the body of the bottle, staining the player's hand if he grips the bottle while the ink is still wet. Also, if the player is using a card which is destroyed after each game he might use the dabber having a large head whereas if the card is to be reused he might want to use a small-headed dabber so that a plurality of spots can be placed on or about the called number. This means that the player has to carry at least two dabbers with him.